Ruta Angustifolia Essential Oil: Behavioral and Insecticidal Effects Against Larvae and Adults of Tribolium castaneum

Abstract

The study aims to evaluate the behavioral and insecticidal effects of Ruta angustifolia EO (RAEO) against larvae and adults of a major pest insect, Tribolium castaneum. RAEO exhibited a strong repellency against both adults and larvae where percentages as high as 74 and 72 % of PR (Percentage of Repellency) were recorded respectively, at 0.47 μL/cm2 after 2 h. Regarding the antifeedant bioassay, no feeding deterrence was recorded in adults while an increase in appetite was registered in larvae exhibiting −80 % of FDI recorded at 0.2 μL/pellet. In terms of feeding preference, the response significantly depended on the developmental stage (F=97.19, P<0.05) and larvae were attracted to treated pellets recording percentages of 84 and 73 % of PI (Preference index) after 5 and 30 min at 0.05 μL/pellet; on the other hand, adults expressed a repulsive behavior at 0.2 μL/pellet with a PI of −81.1 (20 min), and −69.2 % (30 min). Regarding topical application toxicity, a significant difference was observed between larvae and adults (p<0.05 F=174.56). The study promotes the use of RAEO as a repellent and bioinsecticide for the control of larvae and adults of T. castaneum.